The invention relates to compounds and methods for use in biologic systems. More particularly, polyions are utilized for modifying the charge (xe2x80x9crechargingxe2x80x9d) of particles, such as molecules, polymers, nucleic acids and genes for delivery to cells.
Polymers are used for drug delivery for a variety of therapeutic purposes. Polymers have also been used in research for delivery of nucleic acids (polynucleotides and oligonucleotides) to cells, the process is one step in reaching a goal of providing therapeutc processes (gene therapy). One of the several methods of nucleic acid delivery to the cells is the use of DNA-polyion complexes. It has been shown that cationic proteins like histones and protamines or synthetic polymers like polylysine, polyarginine, polyornithine, DEAE dextran, polybrene, and polyethylenimine may be effective intracellular delivery agents while small polycations like spermine are ineffective.
In terms of intravenous injection, DNA must cross the endothelial barrier and reach the parenchymal cells of interest The largest endothelia fenestrae (holes in the endothelial barrier) occur in the liver and have an average diameter from 75-150 nm. The trans-epithelial pores in other organs are much smaller, for example, muscle endothelium can be described as a structure which has a large number of small pores with a radius of 4 nm, and a very low number of large pores with a radius of 20-30 nm. The size of the DNA complexes is also important for the cellular uptake process. After binding to the target cells the DNA-polycation complex should be taken up by endocytosis.
Applicants have provided a process for delivering a compound across the endothelial barrier to the extravascular space and then to a cell.
Described in a preferred embodiment is a process for enhancing delivery of a polyion to a cell, comprising the formation of a complex of polyampholyte and polyion. Then, delivering the complex into a cell.
In another preferred embodiment, we describe a process for extravasation of a complex. The process comprises the formation of a complex of polyampholyte and polyion. Then, inserting the complex into a vessel and delivering the complex to an extravascular space.
Reference is now made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.